ALBANY, N.Y. (AP) -- Nationwide Mutual Insurance Co. has become the first major insurance company to say it won't cover damage related to a gas drilling process that blasts chemical-laden water deep into the ground.

Nationwide spokeswoman Nancy Smeltzer said Thursday the Columbus, Ohio-based company's personal and commercial policies "were not designed to cover" risk from hydraulic fracturing, or fracking.

The process injects chemically treated water into wells to fracture shale thousands of feet underground and release gas or oil. There are rich shale deposits in parts of Pennsylvania, New York, Ohio, West Virginia and elsewhere.

Health and environmental groups claim fracking can contaminate drinking water. The gas industry says it's safe if done properly.

Nationwide says risks involved in fracking operations "are too great to ignore" and apply to policies of commercial contractors and landowners who lease property to gas companies.